Pistons used in gasoline engines, diesel engines, and high performance engines become easily overheated during operation. Pressure actuated oil jets have been used to cool the under side of pistons in such reciprocating engines. Oil jets are often mounted in a bore on the underside of the engine block and receive oil under pressure from an oil gallery. These oil jets also incorporate a check valve to supply oil to the oil jet when a predetermined oil pressure is achieved. Oil jets also prevent siphoning off of needed oil pressure during low oil pressure conditions.
Oil jets spray oil into cooling channels on the underside of pistons, cooling the piston crowns and surrounding cylinder wall by absorbing heat, thus lowering combustion chamber temperatures. This cooling process occurs as the engine is running to reduce piston temperatures, which helps the engine generate more power and assists in lubricating the piston and cylinder wall to increase durability. The extra oil layer on the cylinder bores and reciprocating components also minimizes noise that is typically generated by such components. Keeping an engine running at desired operating temperatures also enhances the life of critical engine parts and reduces maintenance costs over the lifetime of an engine.
There are two standard types of pressure actuated oil jets used in the industry, each comprising a two-part configuration. As shown in FIG. 1, typical pressure actuated oil jets comprise a two-piece construction comprising an oil jet body 10 and an oil jet valve 12. The oil jet body 10 comprises a main body 14 having a valve aperture 16 at one end and a bolt-receiving aperture 18 at the other end. Extending from the sides of the main body 14 are two nozzles 20 which are in fluid communication with the interior of the valve aperture 16.
The valve 12 generally comprises a tubular sleeve 22 having a threaded exterior portion 24 and a pair of oil exiting apertures 26. The sleeve 22 is further connected to an oversized head 28 at one end. When assembling such a two-piece oil jet assembly, the valve 12 is inserted into the valve aperture 16 until the oil exiting apertures 26 of the valve 12 line up with the nozzles 20. The threaded portion 24 of the valve 12 threadedly engages a threaded bore in the lower portion of the engine block and transfers oil under pressure from the oil gallery to the valve 12.
There are generally two valve constructions used in the industry to handle pressure actuation: a ball valve construction (shown in FIG. 1A), and a piston valve construction (shown in FIG. 1B). While both constructions are further described below, it should be understood that for simplicity, like elements are identified by like numbers.
As best shown in FIG. 2, a ball valve 30 comprises a tubular sleeve 32 connected at one end to an oversized head 40. The sleeve 22 further includes a pair of oil exiting apertures 36 that communicate with the nozzles of an oil jet body when the ball valve 30 is placed within a valve body. A bore 38 extends through the head 40 and sleeve 32 to form a passage for oil to enter the ball valve 30. At the end opposite the head 40, the bore 38 tapers to create a seat 42 that is in fluid communication with an oil entrance opening 44.
A spring 46 is held within the bore 38 and biases a ball 48 against the seat 42. When the ball 48 is in contact with the seat 42, the valve is in the closed position. A cap 50 is placed over the bore 38 at the head 40 to retain the spring 46 within the sleeve 32. When the oil pressure is above a predetermined value, the pressurized oil passes through the oil entrance opening 44 and overcomes the spring force to depress the spring 46 and move the ball 48, thereby opening the valve. The pressurized oil enters the bore 38 and exits at the oil exiting openings 36 as indicated by the arrows X and Y in FIG. 2. The oil exiting apertures 36 are in fluid communication with the nozzles in an oil jet body. Therefore, oil exiting the ball valve 30 is directed to the pistons for cooling and lubrication.
When the oil pressure falls below a predetermined value, the spring 46 biases the ball 48 against the seat 42 to close the valve 30. Once the valve is closed, the pressurized oil no longer flows into the valve 30 and pressurized oil is seals and prevents pressure from siphoning off. The valve remains in this state until the pressure once again rises above the predetermined level and overcomes the biasing force of the spring 46.
While cost effective and less susceptible to sticking from debris or contamination, a particular disadvantage with the ball valve construction is that the ball 48 is unstable and is capable of lateral movement within the bore 38 as shown by arrows A and B. The unstable ball 48 begins to vacillate in response to the high-pressure oil flowing past the ball 48. Such vacillation agitates the oil, which causing aeration, i.e., air or other gases mixing with the oil, and decreases the cooling and lubricating effect of the oil.
Another oil jet configuration is a piston valve construction, shown in FIG. 3. A piston valve 52 comprises a tubular sleeve 32 connected at one end to an oversized head 40. The sleeve 32 further includes a pair of oil exiting apertures 36 at its lower end, which communicate with nozzles of an oil jet body. A bore 38 extends through the head 40 and sleeve 32 to form a passage for oil entering the piston valve 52. At the end opposite the head 40 and below the oil exiting apertures 36, the bore 38 tapers to create a seat 42 that is in fluid communicates with an oil entrance opening 44.
A spring 46 is held within the bore 38 that biases a piston 54 against the seat 42 to close the valve. A cap 50 is placed over the bore 38 at the head 40 to retain the spring 46 within the sleeve 32. When the oil pressure rises above a predetermined value, the pressurized oil overcomes the biasing force of the spring 46 to depress the spring 46 and move the piston 54, which opens the valve. When the piston 54 is moved to open the valve, the pressurized oil flows into the bore 38. As the pressurized oil enters the bore 38, it passes through the oil exiting openings 36 as indicated by the arrows Y and X of FIG. 3. Because the oil exiting openings 36 are in fluid communication with nozzles of the oil jet body, the oil is directed onto the pistons. When the oil pressure falls below a predetermined value, the spring 46 biases the piston 54 against the seat 42 to close the valve.
The piston valve design generally reduces the agitation and aeration; however, the piston valve design is more susceptible to sticking from debris or contamination and is much more costly to produce.
Therefore, there is need in the art to create a stable fluid jet that is more cost effective to manufacture and less labor intensive to produce while also being less susceptible to sticking from debris or contamination.